Information storage device



7, 1965 L. G. F. JONES 3,201,769

INFORMATION STORAGE DEVICE Original Filed May 4, 1951 3 Sheets-Sheet lINVENTOR.

LAWRENCE G. F. JONES 7, 1965 L. G. F. JONES 3,201,769

INFORMATION STORAGE DEVICE Original Filed May 4, 1951 3 Sheets-Sheet 2INVENTOR. LAWRENCE GE JONES AGENT Aug. 17, 1965 L. G. F. JONES 3,201,769

INFORMATION STORAGE DEVICE Original Filed May 4, 1951 3 Sheets-Sheet 3FIG.7

INVENTOR. LAWRENCE G.F.JONES AGENT United States Patent ()fiice 339L769Patented Aug. 1?, 1965 3,291,769 ENFGWATHON STGRAGE DEVICE Lawrence G.F. Jones, Baltimore, Md, assignor to Sperry Rand Corporation, New York,N.Y., a corporation of Delaware Uriginal application May 4, W51, Ser.No. 224,610, new Patent No. 2,7$7,75i9, dated Apr. 2, 1957. Divided andthis application dune 6, H56, Ser. No. 589,617

1 l Ciaims. (Cl. 34tl-=-l74.1)

This invention relates to a high speed memory device and/ or systemadapted for use with electronic computing apparatus, having for anobject the provision of a novel stimuli-receiving and inducing sleeve orbearing member and a coacting high speed drum. This application is adivision of my copending application Information Storage Device, SerialNo. 224,610, filed May 4, 1951, now Patent No. 2,787,750, and isassigned to the assignee of said copending application.

There have been previously known arrangements for storing information onand delivering information from a magnetically susceptible surfacesituated on the periphery of a revolving drum. It has been the practiceto suspend the shafts supporting such drums in conventional bearingassemblies, and to mount the magnetic recording and pickup headscooperating with the drum surface at a point or points alon the drumremote from such bearing surfaces.

In general, the surfaces present in the journal or hearing assembly haveplayed no part in the arrangement for storing and deliveringinformation. Since rotating drums, when used for the storage anddelivery of information, must be rotated at very high speeds, of theorder of 20,000 or more, to minimize the delay in referring to a desireditem of information, it is not practical to operate the assembly withthe recording-pickup head in physical contact with the active surface ofthe drum. To do so would rapidly wear away either the operating head orthe drum surface or both. It is therefore necessary to introduce aclearance between the magnetic head and the active surface of the drumwhich is at least equal to the maximum drum eccentricity to beanticipated, the maximum deformation in drum structure to be expected athigh speeds, plus a safety factor. Separation of the magnetic head fromthe active surface of the drum reduces the density with whichinformation may be recorded upon and pick d up from the drum surface, sothat these expedients materially reduce the available storage capacityon a given drum.

In brief, these problems are met by the arrangement of the inventionthrough the incorporation of the magnetic recording-pickup heads in thestructure of the bearing itself, which is the point at which minimumclearances are encountered. As, in one of the embodiments of theinvention, a bearing utilizing a fluid (eg. air) film may be employed,the clearances may be very small, so the drum expansion at very highspeeds may bring the drum surface into engagement with the interior ofthe bearing sleeve. Arrangements will be disclosed which avoid thispossibility.

Accordingly, one of the principal objects of the invention is to providea new and novel information storage system for efficiently utilizing theavailable active magnetic surface.

Another object of the invention is to provide new and novel apparatusfor regulating clearances in a journal or bearing.

invention broadly contemplates the provision of an improved high speedmemory system designed and adapted for incorporation into electroniccomputer apparatus of the type described in publication of the McGraw-Hill Book Company, New York, N.Y., entitled High Speed ComputingDevices, 1st edition, issued 1950.

The high speed memory system contemplated by the present invention lendsitself particularly to incorporation in the high speed computing devicesof the type described in the above-referred to publication, andconstitutes an improvement over the devices described in the latter.

In accordance with the present invention, a stimuli or memory-inducingand receiving sleeve or static member is provided which is adapted tocoact with a high speed, rotatable member or drum revolving at speedswhich may, for example, exceed 50,000 r.p.m. It will be understood, ashereinafter described, that each revolution of the drum will entail theproduction or reception of one or more electric pulses or stimuli thatare impressed on or induced by a plurality of magnetic heads embedded inthe sleeve, each head being capable of receiving or inducing anindividual stimulus.

Referring now to the drawings:

FIGURE 1 is an elevational View, with certain parts broken away forclarity of illustration, depicting an embodiment of the inventionoperatively coupled to a driving motor and incorporating means operativeto associate it with electronic circuit control means;

FEGURE 2 is a plan view of the device;

FIGURE 3 is a longitudinal sectional view taken on line 3-? of FIGURE 2,and as seen in the direction of the arrows;

FIGURE 4 is a transverse sectional view, taken on line d4 of FIGURE 1,looking in the direction of the arrows;

FIGURE 5 is an enlarged, fragmentary sectional detail view of adg'acentportions of the sleeve and drum and disclosing one of the impulsereceiving heads;

FIGURE 6 is a diagrammatic representation of the electric circuitcontrolling the thermal expansion of the sleeve and the speed of themotor to the shaft of which the drum is secured;

FXGURE 7 is a graphical representation of the phase relations of theseveral voltages applied to the thyratron which regulates the heating ofthe sleeve;

FiGURE 8 is a fragmentary enlarged perspective view, partly in section,of one of the two similar capacitor elements fastened to the lowerportion of the sleeve hearing member;

FIGURE 9 is a perspective view of the bracket which serves as a stop forthe static sleeve member; and

FIGURE 10 is an enlarged, fragmentary sectional view of the high speeddrum showing, on a magnified scale, the magnetically-permeable platingor sheath on the periphery of the drum.

Refer now to FIGURE 1. To the bracket lla, the frame of a synchronouselectric motor, designated generally at 14 and having a shaft 14a, isfastened by screws and nuts 15 and 16. On the upper portion of thebracket Ha, a U-shaped member or bracket 17 is fastened as by the screws18, and to the latter bracket, in turn, an angle bar 19 is also securedby the same screws 18. The bracket 17 also serves as a stop for astationary sleeve member hereinafter described more fully. To the upperpart of the angle bar 1%, a finger 2t having a ball point 21 is fastenedby screws 22 and 23. The finger id is adapted to ride in a verticallydisposed guide or groove 24 arranged in the cylindrical wall of astimuli-receiving and inducing sleeve, designated generally at 25. Thevertically disposed guide or groove 24 extends to the lower edge of thesleeve 25 so that the ball point 21 of finger 2% may ride upward in thegroove to its indicated position as the sleeve 25 is lowered verticallyover the drum 55 during assembly. Since there is a hydrodynamic thin airfilm between the sleeve 25 and the drum 55 the viscous drag of this thinair film caused by the high rotational speed of the drum 55 would tendto cause the sleeve 25 to rotate by virtue of the fluid coupling. Suchsleeve rotation is prevented by the finger 20 fastened to the angle bar19.

Referring now to FIG. 3, the upper end of the sleeve 25 is closed by aWeb or top 26 formed integrally therewith and is provided withlongitudinally stretching channels or passageways 28 accommodating thewindings or convolutions of a resistance coil 29 whose ends areconnected to prongs 31 of a plug 32. The plug 32 which permits the coil29 to be coupled to a source of electric energy (not shown) whendesired, is fastened to the web 26 by a screw 33. The annular recess 27is normally closed by a cover 34 having an opening 35 to accommodate thebody portion of the plug 32.

The web or top 26 of the sleeve 25 has a centrallypositioned threadedopening 36 communicating with a reduced passageway 37 opening intotheinterior of the sleeve 25. The opening 36 accommodates a manuallyoperable valve 38 that serves to admit air to the interior of thesleeve.

As shown in FIGURE 3 and FIGURE 4, adjacent the lower end of the sleeve25, and embedded therein so as to present a substantailly flushcontinuation of its inner periphery, is a pair of capacitor elements 53,54 which coact with a metallic, air-supported high speed rotatable drum55, located within said sleeve and hereinafter described more fully, toprovide a variable capacitor. This capacitor is connected to and servesto affect or regulate an electronic circuit that in turn is effective toregulate the speed of the synchronous driving motor 14 fastened to thedrum alluded to by shaft 14a.

Each of the capacitor elements 53, 54 as shown in cross-section byFIGURE 8 includes a metallic body portion -6, of an approximatelyT-shaped contour, secured to suitable insulating material 56a, as by thescrews 57. The insulating material 56a also has a configuration adaptedto conform to the metallic body portion which has a laterally-extendingtongue 58, accommodated in a slot 59 formed in a rib 60 of theinsulating material. The outer edge or surface of the metal tongue 58,it is to be understood, is in alignment and merges with the adjacentouter edges of the insulating material defining the slot 59:; and, whenthe capacitor element is operatively attached to the sleeve 25, the saidouter edge of the tongue 58 is smoothly flush with the inner peripheryof the latter and in extremely close proximity to the outer periphery ofthe rotatable drum 55. By means of the construction described, it willbe understood that the capacitor elements 53, 54 are individuallyinsulated from the body portion of the sleeve 25.

In further accordance with the invention, the sleeve 25 is provided witha plurality of stimulus-receiving and inducing, magnetic-recordingmembers or heads 39, best shown in cross-section in FIGURE 5 embedded inthe sleeve 25 and arranged thereon in staggered or helical fashion. Thishelical or staggered positioning of the magnetic-recording heads isdesigned to afford their closer spacing so that a greater number may beemployed, if desired.

The interior of the bearing sleeve is preferably honed and lapped afterthe insertion of the magnetic recording-reproducing heads. The exteriorof the drums may then be finished to fit within the resultant openingwith the required degree of precision. While the sleeve mounting hasbeen illustrated as a floating mount, this is not essential to therealization of the advantages of the invention which may be retained aswell with a rigidly supported sleeve.

Each head 39 includes a body portion 39:: formed of a suitablenonconducting or insulating substance such as plastic material,celluloid and the like, in which is embedded a substantiallyrectangular-shaped armature element or core 40, formed of a preferablyparamagnetic alloy or metal. The armature 40 has its ends or poles 41,42 arranged in closely-spaced, opposed relation and 4 has a Winding orcoil 43 encircling its central reach 44 that connects with arms 45, 46terminating in the abovementioned inwardly-directed and opposed poleends 41, 42.

The ends of the coil winding are attached to a pair ofcircuit-completing prongs 49, 5t) protruding externally from the plasticbody portion of its respective head and located with a collar or bushing51 threadedly engaged with a reduced exterior portion of the bodyportion of the said head. The collar 51 has an outer annular flange 52which seats snugly on the periphery of the sleeve 25.

The high speed drum 55 as shown in FIGURE 10, comprises a cylindricalbody portion 55a which may be of any suitable alloy or metal, butpreferably of the highest tensile and strain-resistant properties, as,for example, stainless steel, and a thin plated sheath or coating 55b ofa magnetically permeable material adapted to receive and retain magneticstimuli so that information and data may be both received andtransmitted by the instant device and for use with electronic computingdevices of the general type alluded to above. A 0.0002 inch layer ofnickel-cobalt alloy has been found suitable for the coating 55b.Reference to FIGURE 1 shows the reduced hub portion 61 at the lower endof drum 55 which is adapted to accommodate and securely retain the shaft14a of the motor 14.

The mode of controlling the expansion and contraction of the sleeveproportionately to the expansion and contraction of the high speedrotating drum, and also of regulating the speed of the synchronous motorin such wise as to gradually accelerate it to the enormous rpm. forwhich it is intended and then to correspondingly decelerate it, has beengenerally alluded to above.

The electronic control means employed for attaining the objectivesmentioned is shown in FIGURE 6 and utilizes oscillatory and associatedcircuits whose interlocked outputs are selectively applied to controlcircuits. One of these circuits is associated with athermally-responsive assembly, hereinafter described more fully and hasan independent branch circuit effective to gradually accelerate anddecelerate the motor over a space of time sufiicient to permit thecorrespondingly gradual heating or cooling of the resistance coil 29 inthe sleeve 25 in order that the latter may vary its dimensionsproportionately to the drum, and thus maintain an extremely close, yetuniform, spacing between the sleeve and the said drum.

Referring now to FIGURE 6, an oscillatory circuit is indicated generallyat 63. This includes a pentode 64 whose control grid 65 is coupled to acapacitor formed by interaction between the high speed drum 55 and thepair of connected capacitor elements 53, 54 on the sleeve 25. In orderto regulate or confine the oscillatory circuit 63 to a desired range offrequencies, a variable capacitor 66 is connected in parallel with thecapacity formed by the elements 53, 54 and the drum 55, so that, after adesired preliminary setting of the manually variable condenser 66, thecapacity between the drum and sleeve will be substantially the solefactor in varying the frequency of the said oscillatory circuit 63. Acapacitor 66a completes the connection of the control grid 65 of thepentode 64 with the oscillatory circuit.

As best shown in FIGURE 4, each of the capacitor elements 53, 54 hasfastened thereto a binding post 53a, 54a having a set screw to secureits respective lead to the capacitor 66.

The output of the pentode 64 of the oscillating circuit 63 is coupled,via condenser 67 and resistor 68, to a mixer valve 69 where it iscombined, via lead 69d and capacitor 69c, with the output of acrystal-controlled oscillator circuit 70 which includes the pentode 71and an associated doubler circuit having the triode 72.

The signal from the mixer 69 is applied, via an inductance-capacity lowpass filter circuit 6%, coupling condenser 69b and resistance 690, to anamplifier valve 73 whose output is fed to a conventional discriminatorcircuit, indicated generally at 74, and including the duodiode 75. Theoutput of the latter is fed, via the lead 75a, to an inverter 76 coupledin turn, via the resistor 77 to the grid of a thyratron 78 whose anodeis connected to one end of the secondary winding of a transformer '79.The other end of the same transformer Winding is con nected through aninductance 7% to the resistance or heater coil 43 in the sleeve 25. Theinductance 79a is associated with a grounded capacitor 79d and functionstherewith as a hash filter to prevent radiation interference.

The primary winding of the transformer 79 is coupled to and energized bya 60 cycle source of electric energy 7% and is also connected to aresistance capacity filter section, indicated generally at 790, in turnconnected to the control grid of the thyratron 78. When the thyratron isfired, via the circuit components indicated above, it will be effectiveto apply a heating current or pulse to the coil 43 in order to variablyheat same in order to vary the diametral dimensions of the sleeve 25.

The voltages delivered to the thyratron 78, and the circumstances underwhich it is fired, as mentioned above, are indicated in FIGURE 7. Thesine wave, indicated in light out-line, and which oscillates about theZero axis, represents the potential applied to the anode of thethyratron. The sine wave curve shown in heavy outline represents the AG.component of the potential impressed upon the control grid of thethyratron, and oscillates about the axis shown in heavy outline whichrepresents the DC. potential impressed from the inverter tube 76 uponthe control grid of the thyratron. The curve delineated by the dashedline represents the control grid potential required to trigger thethyratron.

The output of the discriminator circuit 74 is also delivered via thelead 80, with an interlocking circuit net- Work, which includes thediode 83. connected to a reactance valve 32 coupled to aninductance-capacity circuit 83 in turn connected to a pentode 84 servingas oscillator and mixer valve.

The circuit 83 includes two variable condensers 8d, 86a, the shaft orother equivalent component of the latter being mechanically connected orlinked, as indicated by the dashed line 86b, to the bimetallic blade orexpansion coil of a thermostat assembly, denoted diagrammatically at 87,which may be of conventional construction. A heater resistance 88,associated with the bimetal 87, is connected through a switch 89 to asuitable A.C. supply source which may be independent of the electroniccontrol means employed in this invention.

The thermostat assembly 87, it will be understood, is enclosed in ahousing (not shown) of temperature-resistant material so that there willbe an appreciable time lag with respect to temperature changes after theresistance winding 88 has conditioned the thermostat coil or element toslowly turn the shaft of the variable condenser Sda to vary its capacityin order to bring the synchronous motor 114 to the high rpm. desired inthis system, and maintain it substantially thereat while the device isin operation. When the bimetal 3'7 has reached a sufiicient temperature,further change in the capacitor 86a is prevented by an adjustable stop,settable to regulate the drum speed.

The mixer tube 84 receives the output of a crystalcontrolled oscillatorcircuit (indicated generally at 9%) which includes pentode 91 whoseplate circuit 92 is coupled, via the capacitor 93, to the said mixertube 84. The beat frequency from the mixer tube 84 is applied via thefilter circuit, indicated generally at 93a, to an amplifier 94 whoseoutput, in turn, is coupled to the synchronous motor 14 whose shaft Mais mechanically connected, as indicated by the dashed line 14a in FIGURE6, with the high speed drum 55.

A sprocket channel may be incorporated on the drum to provide thedesired relationship between the information on the drum and the timesequences observed in the circuits external thereto; its output would beapplied to conventional phase detector circuits to feed the input of thereactance valve 82.

The manner of operation of the device has in part been indicated above,but will be more fully understood from the following explanation:

The starting operation will best be understood by reference to FTGURE 6.In the absence of heat from the resistor 88, the spiral bimetallicelement 87 maintains the capacitor 86a in its maximum capacity position.The oscillations generated by the interelectrode assembly of the mixervalve 84 under these conditions may be approximately 30 cycles persecond higher than the oscillations generated by the crystal-controlledoscillator 90, both of the oscillators operating in the region of 100kilocycles per second. This insures that under stand-by conditions thesynchronous motor 14 will be excited at a frequency of 30 cycles persecond and thus the drum 55 will be driven at stand-by at a speed of1800 rpm. This relatively low constant speed keeps the air or otherfluid lubricant film intact, preventing metal-to-metal contact betweenthe drum and the embracing sleeve.

The apparatus is placed in service by closing the switch 89 whichexcites the heater 8%, gradually warming the bimetallic element 87,which drives the variable capacitor 86a in the circuit 83 associatedwith the valve 84 toward its minimum capacity position. The thermal timeconstant of the bimetallic element and resistor assembly may berelatively long, for example, of the order of 10-15 minutes. At the endof this time period, the capacitor 86a abuts an adjustable stop limitingthe decrease in capacity. As the frequency of the oscillations generatedby the interelectrode assembly of the valve 84 is higher than thatdeveloped in the crystal-controlled oscillator 9d, the gradual motion ofthe bimetallic element 87 gradually increases the frequency applied tothe synchronous motor lid from 30 cycles per second to, say, 1000 cyclesper second, when the motor 14- revolves at 60,000 rpm. By virtue of theconnection 14a to the drum 55, the drum 5'5 is caused to revolve at thesame speed.

As the speed of rotation of the drum 55 increases, centrifugal forcecauses an expansion thereof bringing its rotating periphery into closerassociation with the capacitor electrodes 53, $45. These electrodescontrol the frequency developed by the oscillator valve 64 which maynormally operate at a frequency of about 20 megacycles per second.Increasing speed of the rotor 55 diminishes the operating frequency ofthe oscillator 64, and thus reduces the frequency applied to the innercontrol grid of the valve 6%.

The oscillatory output of the valve 69 is combined with the output ofthe frequency doubler 72 whose input may be excited from thecrystal-controlled oscillator 7d. The suitable value for the frequencyof the oscillator 79 would be 15 megacycles per second which, afterdoubling, results in a frequency of 30 megacycles per second at theoutput of the valve '72. A different frequency of, nominally, tenmegacycles per second appears in the output of the valve 659 and isdelivered through the low pass filter 69a to the control grid of a valve73 driving a discriminator assembly. The output frequency from the mixer69 increases from its center value of 10 megacycles per second inresponse to the expansion of the rotor 55 and the discriminator 74 is soconnected that under these conditions, i.e. increasing an inputfrequency above ten megacycles per second, the line 75a is drivennegative.

The control grid of the valve '76 is fed, through aresistance-capacitance filter, from the line 75a and the in creasinglynegative bias diminishes the flow of anode current through the valve '75to apply progressively more positive potentials to the control grid ofthe thyratron 78 through the coupling resistor 77. An increasinglypositive reference potential on the control grid of the thyratron '78increases the flow of current in its anode 7 circuit and hence the fiowof current through the heater 43 associated with the bearing shell. Thisincreases the inner diameter of the bearing shell tending to restore theinitial clearance.

In the meantime, however, the bimetallic element 87 continues to drivethe capacitor sea towards it minimum capacity position, and as thiscapacity decreases at too great a rate, the speed of the drum, and itsdiameter, may increase at a greater rate than the increase in the innerdiameter of the bearing shell from the heat developed in the resistor43. Damage from this source is prevented by the connection of the line75a to the cathode of the diode 81, which is normally nonconductive.However, when the line 75:; becomes more than two volts nega tive,conduction is established through the diode 81 to apply a more negativepotential to the auxiliary control grid of the reactance valve 82diminishing the lagging current drawn by this valve from the oscillatorycircuit including the capacitors $6 and 86a. This control action reducesthe frequency developed by oscillatory action in the inter-electrodeassembly of the mixer valve 84, thereby opposing further increase in theoutput frequency of the mixer 84 which would be caused by continuingchange in the value of the capacitor The control action exerted by thereactance valve 82 is proportioned to override the action of thecapacitor 86a under these conditions thus preventing further increase inthe drum speed until the inner diameter of the bearing shell hasincreased sufiiciently to release the oscillator 84 from suchsupervisory control. When restoring the apparatus to stand-by condition,the switch 89 is opened thereby cutting off the source of electricenergy from the resisto 88; whereupon the bimetallic element 87 slowlycools reducing the beat frequency in the anode circuit of the valve 84and gradually returning the speed of the rotor 55 to its standby speedof 1800 r.p.m.

It will, of course, be understood that the description and drawingsherein contained are illustrative merely, and that various modificationsand changes may be made in the structure disclosed without departingfrom the spirit of the invention.

What is claimed is:

1. In combination, magnetic transducer means, a cylindrical magneticrecording medium adapted for rotation about its axis and past saidtransducer means, a member supporting said transducer means andenclosing said medium in spaced relationship thereto, a fluid interposedbetween said medium and said member, said fluid being moved along withsaid medium at a speed sufiicient to provide bearing support betweensaid medium and said member for maintaining said transducer means inspaced relationship to said medium during rotation of said medium.

2. In combination, magnetic transducer means, a magnetic recordingmedium adapted for motion past said transducer means, a support memberfor said transducer means, and a fluid between said medium and saidmember and carried by the motion of said medium so that motion impartedto said fluid by said medium maintains said member in substantiallyconstant spaced relationship to said medium.

3. In combination, a plurality of magnetic transducers, a cylindricalmagnetic recording medium adapted for rotation about its axis and pastsaid transducers, a member in bearing support relation to and enclosingsaid medium, said bearing support relationship being provided by a fluidbearing established in response to the rotation of said medium, saidmember supporting said transducers and maintaining them in spacedrelationship to said medium, said transducers being so disposed aboutsaid member that each of said transducers may be magnetically associatedwith a ditferent circular band on the cylindrical surface of saidmagnetic recording medium.

4. In combination, magnetic transducer means, a magnetic recordingmedium in close spaced relation to said transducer means, means forproducing relative motion between said transducer means and saidrecording medium, a fluid interposed between said transducer means andsaid recording medium said transducer means and said recording mediumbeing operable to form from said rluid a bearing therebetween inresponse to said relative motion for maintaining said transducer meansout of physical contact with said recording medium.

5. A magnetic memory device comprising a cylindrical magnetic recordingmedium, a magnetic transducer in close spaced relation to said recordingmedium, means for supporting said transducer, means for producingrelative motion between said recording medium and said support means inmanner to product between said recording medium and said support means afluid film which is such as to maintain said close spaced relationship.

6. In combination, a transducer means, a recording medium in closespaced relation to said transducer means, means for producing relativemotion between said transducer means and said recording medium, a fluidbetween said transducer means and said recording medium operable inresponse to the relative motion of said means and said medium to form afluid film therebetween for maintaining said close spaced relation.

7. A recording apparatus comprising a bearing member carrying arecording element, a movable recording medium, means for moving saidrecording medium proximate said bearing member to move ambient fluidagainst said member, mounting means for said member and said mediumallowing variations in the spacing between said member and said medium,and responsive to the force of said ambient fiuid moved by said mediumto provide spacing between said member and said medium while maintainingrecording communication therebetween.

8. In combination, a cylindrical magnetic recording medium adapted forrotation about its axis, magnetic transducer means, a cylindrical membersupporting said magnetic transducer means in recording relationship withsaid medium, a fluid interposed between said member and said medium,said fluid forming a fluid bearing between said member and said mediumin response to rotation and said member to maintain said transducermeans in constant recording relationship to said medium.

9. In combination, magnetic transducer means, a cylindrical magneticrecording medium adapted for rotation about its axis, a member enclosingsaid medium, said member having a cylindrical interior surface, saidtransducer means being supported by said member to 'be flush with saidinterior surface of said member, and a fluid interposed between saidmember and said medium to form a fiuid bearing therebetween in responseto rotation of said medium, said fluid bearing being effective tomaintain a close spaced relationship between said transducer and saidmedium.

It A magnetic recording system comprising a first recording elementincluding a magnetic recording medium, a second recording elementincluding a magnetic transducer for reading and writing signals on saidrecording medium, a fluid between the surfaces of said recordingelements, means moving one of said elements in a certain direction andat a speed suflicient to provide a certain movement to form a film ofsaid fluid adjacent said one of said elements, means for supporting theother of said recording elements with its surface having a certain closespaced relation to said surface of said one recording element and to bemovable toward and away from said one recording element and transverseto said certain direction of movement, said means for supporting saidother recording element including means for constraining said otherelement from movement with said moving film and for positioning saidother element upon movement away from said close spaced relationship tobe acted upon by said moving film to be returned thereto, whereby saidmoving film is operative to maintain said 9 close spaced relation forthe reading and writing of signals on said recording medium by saidmagnetic transducer.

11. In combination, a first record receiving element, a second recordproducing element, a fluid interposed between said first and secondelements, means for maintaining a desired uniform clearance between saidelements for transmission of signals therebetween, said clearancemaintaining means including means providing relative motion between saidfirst and second elements to cause said elements to scan one another andto establish therebetween by virtue of the motion of one of saidelements a rapidly moving film of said fluid effective to maintain saiddesired clearance.

12. In combination, a magnetic drum mounted for rotation about a fixedaxis, a magnetic recording and reproducing head, means for mounting saidhead to prevent rotation of said head about the axis of said drum and toallow lateral motion of said head toward and away from said drum toallow positioning of said head to a desired small clearance with thesurface of said drum, a fluid interposed between said drum surface andsaid head, and means rotating said drum at a speed suflicient toestablish between said drum surface and said head by virtue of therotation of said drum a high velocity film of said fluid operable tomaintain said desired small clearance.

13. In combination, magnetic transducer means, a magnetic recordingmedium of circular cross section adapted for rotation about its axis andpast said transducer means, a member supporting said transducer meansand enclosing said medium in spaced relationship thereto, a fluidinterposed between said medium and said member, said fluid being movedalong with said medium at a speed sutficient to provide bearing supportbetween said medium and said member for maintaining said transducermeans in spaced relationship to said medium.

14. In combination, a plurality of magnetic transducers, a cylindricalmagnetic recording medium adapted for rotation about its axis and pastsaid transducers, a cylindrical member enclosing said medium in bearingsupport relation thereto, said member supporting said transducers inrecording relationship to said medium, a fluid interposed between saidmember and said medium for forming a fluid bearing therebetween inresponse to the motion of said fluid during rotation of said medium tomaintain said transducers in spaced relationship to said medium, saidtransducers being disposed about said member along a helical path, theaxis of said helical path coinciding with the cylindrical axis of saidmember.

15. The combination according to claim 14 wherein said member comprisesa cylindrical sleeve the inner surface of which is closely spaced fromsaid medium.

References Cited by the Examiner UNITED STATES PATENTS 2,038,216 4/36Harrison et a1 179-100.2 X 2,144,844 1/39 Hickman 79-100.2 2,512,3726/50 Pakala 318-6 X 2,540,654 2/51 Cohen et al 34674 2,603,539 7/52Brewster 179-100.2 X 2,671,700 3/54 Seyffert 179-1002 X 2,700,588 1/55Williams et a1. 34674 2,708,693 5/55 Hendrickson 179-1002 IRVING L.SRAGOW, Primary Examiner.

NEWTON N. LOVEWELL, L. MILLER ANDRUS,

STEPHEN W. CAPELLI. Examiners.

1. IN COMBINATION, MAGNETIC TRANSDUCER MEANS, A CYLINDRICAL MAGNETICRECORIDNG MEDIUM ADAPTED FOR ROATION ABOUT ITS AXIS AND PAST SAIDTRANSDUCER MEANS, A MEMBER SUPPORTING SAID TRANSDUCER MEANS ANDENCLOSING SAID MEDIUM IN SPACED RELATIONSHIP THERETO, A FLUID INTERPOSEDBETWEEN SAID MEDIUM AND SAID MEMBER, SAID FLUID BEING MOVED ALONG WITHSAID MEDUM AT A SPEED SUFFICIENT TO PROVIDE BEARING SUPPORT BETWEEN SAIDMEDIUM AND SAID MEMBER FOR MAINTAINING SAID TRANSDUCER MEANS IN SPACEDRELATIONSHIP TO SAID MEDIUM DURING ROTATION OF SAID MEDIUM.